1. Field of the Invention
This invention relates to electronic connector apparatus and more particularly to integrated circuit component sockets. The devices of this invention are particularly useful for electrically connecting crystal oscillators of various speeds to computer circuit boards.
2. Background
In a typical computer system today, many circuits are controlled by surface mounted crystal clock oscillators such as those supplied commercially by SaRonix, Pletronics, Inc. and others. The Pletronics SM1100 series of surface mount clock oscillators is a more specific exemplary type. Most computer systems installed today use clock oscillators at speeds below 40 MegaHertz (MHz). At these speeds oscillators have relatively low failure rates so that heretofore there has been little need for frequent replacement of the oscillator modules.
New computer systems are being designed to run at faster and faster speeds, requiring clock oscillators which run at 60 MHz, 80 MHz, and higher. Such higher speeds require design modifications of many of the standard circuits in these computer systems in order to avoid problems such as pulse echo, non-synchronization of multiple clocks, or general synchronization and reaction to more frequent clock pulses, etc. These circuit redesigns typically are tested at the prototype stage at low clock rates (for example, 20 MHz), and the clock rates then increased in a step-wise manner to isolate any rate-related problems. This step-wise increase in the clock rate is accomplished by demounting the 20 MHz clock oscillator, and mounting in its place a higher rate oscillator, say 40 MHz for example, and then retesting the circuits, boards, etc. with the higher clock rate. This procedure of de-mounting the clock oscillator module and mounting a higher rate module might be repeated with a 60 MHz module for additional retesting, and so on up to the highest clock rate for the particular circuit design.
A similar procedure occurs with these higher rate circuits during maintenance operations. In many cases, an apparent logic or circuit anomaly may not be correctly diagnosed or isolated without lowering the clock rate of the circuit. This requires removal (de-mounting) of the installed clock oscillator (for example an 80 MHz unit) and remounting a slower unit (for example a 40 MHz) in order to operate the circuit at the lower rate.
The problem which occurs in both the case of prototype testing and routine maintenance, is that there is no easy way to mount and de-mount the clock oscillator modules. All available clock oscillator modules are designed with either "J" leads compatible with the Electronic Industries Association (EIA) standard surface mount land pattern, or with "Gull-Wing" leads compatible with the semiconductor industry standard, SO-L-20 surface mount land pattern. These designs result in a mounting and de-mounting operation that typically requires removal of the circuit board involved, desoldering and often destructive removal of the installed unit, board cleanup, inserting of the new unit and resoldering. This procedure typically results in one-half to one and one-half days of reconfiguration effort on complex prototype boards, and unnecessarily increases development time and cost. This complex procedure for de-mounting and remounting a different clock makes trouble isolation and repair a difficult and time consuming task for service technicians. Thus there is a need for an apparatus which simplifies the insertion and replacement of clock oscillator modules. This need is further due to the dramatic increases in clock frequencies used by newer computer components, and the increasing density and complexity of related circuits and circuit boards.
Test sockets for integrated circuit devices have long been designed to allow easy and rapid replacement for mass testing and observation. Most such devices are designed for specific circuit modules. In the past, connector or socket type devices have been used or proposed for modules such as memory modules which can be added incrementally to a circuit board, or special configuration identification modules for parameters which change from time to time such as an ethernet address module. Such socket type devices generally contain female type jack assemblies into which the pins of the removable modules are inserted. However, many devices which are mounted on printed circuit boards have formed leads instead of pins such as the "J" leads of clock oscillators mentioned above. Socket assemblies to accommodate formed leads are not available for such devices as clock oscillator modules. The present invention fills this need.
An additional problem which has been experienced by users of pin type socket devices for component testing has been difficulty in obtaining acceptable electrical contact between the pins of the device being tested and the socket contacts. This problem is magnified when surface mount components are considered for use with sockets. However, the construction of the present invention provides greater surface contact and hence better electrical contact between the formed leads of the device and the socket contacts than the device normally has with the printed circuit board.
The socket apparatus of the present invention fills this need, and overcomes the shortcomings of the prior art devices as they relate to use with such surface mounted components.